Honestly, I'm still trying to figure out how to use this site, but here are some tips that won me some games. As in two.

Early Game - Invade Level 1. You've got to get that gold advantage as soon as possible and delay the enemy Jungler's clear. Since the river is your domain, you want as much control over it as possible to get those damn crabs.

Ganking - Focus on two lanes to gank the most. Be sure to gank when the enemy is pushing or low. When the enemy Jungler is dead or on top side, go for Dragon if possible, otherwise help push bot. Get your Mid Laner as fed as you can so they can snowball the rest of the game. Let your Top Laner take Herald so you don't have to worry about drawing pressure there.

Farming - You shouldn't be farming too much as River Tomato, but if you do, take the enemy's camps. It's more of a hindrance to them that their Raptors are gone than it is to you if yours are gone. If your team needs to, help them farm jungle camps as well.

Split Pushing - Since you're probably going to be lower leveled than the rest of your team, you'll be the one split pushing the most when behind unless there's a massive teamfight. Focus on lanes with fewer turrets and push those waves until your team needs you or you're about to get molly***ped.